English

A Harder-Narasimhan stratification of the $B_{dR}^+$-Grassmannian

Algebraic Geometry 2022-12-21 v2 Number Theory

Abstract

We establish a Harder-Narasimhan formalism for modifications of GG-bundles on the Fargues-Fontaine curve. The semi-stable stratum of the associated stratification of the BdR+B_{dR}^+-Grassmannian coincides with the variant of the weakly admissible locus defined by Viehmann, and its classical points agree with those of the basic Newton stratum. When restricted to minuscule affine Schubert cells, the stratification corresponds to the Harder-Narasimhan stratification of Dat, Orlik and Rapoport. We also study basic geometric properties of the strata, and the relation to the Hodge-Newton decomposition.

Keywords

Cite

@article{arxiv.2111.01764,
  title  = {A Harder-Narasimhan stratification of the $B_{dR}^+$-Grassmannian},
  author = {Kieu Hieu Nguyen and Eva Viehmann},
  journal= {arXiv preprint arXiv:2111.01764},
  year   = {2022}
}